% \begin{tikzpicture}[every node/.style={minimum size=1cm,draw}, >=Stealth]
%     \coordinate (a) at (0, 0);
%     \foreach \text  [count=\i] in {
%         输入$x$, $-2$, $\times 3$, $+1$,  输出$y$
%     } {
%         \ifnum \i > 1 \relax
%             \draw [->] (N.east) -- +(0.5, 0) coordinate (a);
%         \fi
%         \draw (a) node [right] (N) {\text};
%     }
% \end{tikzpicture}
\begin{tikzpicture}[every node/.style={minimum size=1cm,draw}, >=Stealth]
    \graph [grow right sep=0.5cm] {
        "输入$x$" -> "$-2$" -> "$\times 3$" -> "$+1$" -> "输出$y$"
    };
\end{tikzpicture}
% 不使用 \graph 的写法见 czds4-ch14-xiti4-1-1
